Meta System Design Interview Questions
Practice 1,159 real Meta interview questions for 2026. Covers top categories — Coding & Algorithms, Analytics & Experimentation, Data Manipulation (SQL/Python), Behavioral & Leadership, and System Design — across Software Engineer, Data Scientist, Machine Learning Engineer, Data Engineer, and Product Manager roles. Real questions from actual interviews with detailed solutions. Expect a software-engineering-heavy loop: timed algorithmic coding (trees, arrays, graph/maze problems, delimiter/CSV parsing), system-design prompts like leaderboards, flight search and online-judge architectures, and an increasingly common AI-assisted coding round that mirrors real workflows. Data Scientist rounds emphasize product analytics and experimentation—designing tests, diagnosing spend drops and bots, evaluating unconnected content, and writing SQL for multi-account, seller, and vehicle metrics. Machine Learning Engineer questions skew toward recommender and ranking work (place and friend recommendation, sparse-matrix ops, linear-regression derivations, newsfeed dislike models). Data Engineers focus on data modeling, ETL, capacity calculations, reservations/utilization queries, and production SQL/Python tasks. For interview preparation, prioritize timed coding practice, system-design templates, rigorous SQL drills (joins/CTEs/aggregation), clear A/B-testing frameworks, and concise STAR behavioral stories tied to measurable impact.

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"I recently cleared Uber interviews (strong hire in the design round) and all the questions were present in prachub."
"The search is what sold me. I typed in a really niche DP problem I got asked last year and it actually came up, full breakdown and everything. These guys are clearly updating it constantly."
Join datasets and compute conversion by assignment
You are given two CSVs. Create tables and write SQL to produce both visit-level and visitor-level conversion datasets, then aggregate conversion by as...
Solve BST range average and merge intervals
1) Given a binary search tree and an inclusive range [L, R], compute both the sum and the average of all node values where L <= val <= R. Use the BST ...
Compute capacities after site closures
You are given a nested dictionary redistribution where redistribution[closed_site][dest_site] equals the additional capacity required at dest_site if ...
Implement string dedup and mirror tree traversal
- String cleanup with group deletions (LeetCode-inspired): Given a string s consisting of lowercase letters, repeatedly delete any maximal contiguous ...
Implement BST vertical traversal and list conversion
Given the root of a binary search tree (BST): 1) Implement vertical order traversal: assign the root column 0, left child column −1, right child colum...
Compute left and right views once
Given the root of a binary search tree, output two lists: the nodes visible from the left side and the nodes visible from the right side, from top to ...
Find kth smallest in sorted matrix
Given an n x n matrix where each row and each column is sorted in nondecreasing order, and an integer k (1 ≤ k ≤ n^ 2), return the k-th smallest eleme...
Compute longest rising path in a grid
Given an m×n grid of integers, find the length of the longest path where each step moves up, down, left, or right to a strictly larger value. Return t...
Fill rooms with nearest gate distances
You are given an m×n integer grid representing rooms, where -1 is a wall, 0 is a gate, and INF (a large sentinel such as 2^31− 1) is an empty room. Fo...
Find connected region sizes in matrix
Given an m x n grid of characters grid and a target character ch, implement: ( 1) sizeOfRegion(grid, r0, c0, ch) -> int that returns the size of the 4...
Solve grid path and robot navigation
Part A — Shortest path in a grid with obstacles: Given an m×n grid of 0/1 cells (0 = open, 1 = obstacle), start at (0, 0) and end at (m−1,n− 1). You m...
Implement power and balance-parentheses algorithms
Design and implement two algorithms: 1) Fast exponentiation: Implement a function pow(x, n) that returns a real number x raised to an integer exponent...
Count subarrays equal to target
Given an integer array nums and an integer k, return the number of contiguous subarrays whose sum equals k. Provide an algorithm better than O(n^ 2), ...
Optimize SQL to minimize scans
Given a large analytics query, refactor it to minimize table scans. 1) Replace unnecessary CTEs that cause multiple scans with inline aggregations or ...
Optimize flight costs and find grid path
1) Given two integer arrays D and R of equal length n, where D[i] is the cost to depart on day i and R[j] is the cost to return on day j, choose indic...
Find kth smallest pair sum with heaps
You are given two nondecreasing arrays A (length n) and B (length m) of non-negative integers and an integer k (1 <= k <= n*m). Return the k-th smalle...
Find top-K frequent values with tiebreaks
Question Given an integer array nums and an integer k, return the k values with the highest frequency. The array can contain up to 10^6 elements. When...
Merge two interval lists into a union
You are given two lists of closed intervals [start, end]. Each list is individually sorted by start and contains non-overlapping intervals. Merge the ...
Design LCA and find K closest points
Part A — LCA with parent pointers: You are given two nodes a and b in a rooted tree where each node has a parent pointer (you may or may not have dire...
Compute binary tree left-side view
Given a binary tree, return the values visible from the left side when looking from top to bottom. If multiple nodes exist at the same depth, the left...